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Study : The Extreme Male Brain Theory of Autism Revisted

Posted Apr 14 2012 12:03pm
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The extreme male brain theory of autism is the idea that many of the traits of autism can be looked at as extreme versions of traits that are common in men.  Autism could then be "caused" by something that takes an ordinary brain and then turns up the male features of the brain and turning down the female features.

Or something like that.

To be honest, I have never really liked the theory.  Maybe that is because I have daughters with autism or maybe it is because I don't buy into the stereotypes of what men are supposed to be like.

Or, just maybe, it is because there is very little data to support the theory.  It is one thing to look at some high-function people with autism and come up with a theory of how they think but it quite another to actually have real data that supports the theory.  And no, 2D:4D finger ratios and  preferred hip-waist ratios don't count as real data.

Regardless, I found this study that was just published to be rather informative and funny at the same time.  The abstract is below.
BACKGROUND: The 'extreme male brain' theory suggests that autism spectrum disorder (ASD) is an extreme variant of male intelligence. However, somewhat paradoxically, many individuals with ASD display androgynous physical features regardless of gender.
AIMS: To assess physical measures, supposedly related to androgen influence, in adults with and without ASD.
METHOD: Serum hormone levels, anthropometry, the ratio of 2nd to 4th digit length (2D:4D) and psychiatric symptomatology were measured in 50 adults with high-functioning ASD and age- and gender-matched neurotypical controls. Photographs of face and body, as well as voice recordings, were obtained and assessed with respect to gender coherence, blindly and independently, by eight assessors. 
RESULTS: Women with ASD had higher total and bioactive testosterone levels, less feminine facial features and a larger head circumference than female controls. Men in the ASD group were assessed as having less masculine body characteristics and voice quality, and displayed higher (i.e. less masculine) 2D:4D ratios, but similar testosterone levels to controls. Androgynous facial features correlated strongly and positively with autistic traits measured with the Autism-Spectrum Quotient in the total sample. In males and females with ASD dehydroepiandrosterone sulfate did not decrease with age, in contrast to the control group. 
CONCLUSIONS: Women with ASD had elevated testosterone levels and several masculinised characteristics compared with controls, whereas men with ASD displayed several feminised characteristics. Our findings suggest that ASD, rather than being characterised by masculinisation in both genders, may constitute a gender defiant disorder.
So now, instead of autism being "characterised by masculinisation in both genders", it is now suggested that it "may constitute a gender defiant disorder"...

Really?   It was bad enough to suggest that autism was just being too masculine.  Do we really want to another theory that suggests that autism is all about gender ambiguity?  I'm sure that will go over well.

And what about the non-"high functioning" people with autism, otherwise known as the majority of people with autism, why are they excluded - yet once again - from a study like this?  If you are trying to test the validity of a theory of autism spectrum disorders perhaps it would be beneficial to test it against the majority of people with autism.

But, on a more serious note, there are two bits in the abstract that are interesting and both speak to an ongoing biological process.

First, why would the women with autism have a higher level of testosterone and what exact process would cause a women's testosterone level to remain elevated throughout her life?

Second, why would older males and females with autism have a higher level of  dehydroepiandrosterone  sulfate than the controls?  My knowledge is more than a little lacking in this area, but from what I understand the body uses steroid hormones like this to help control metabolism, inflammation, immune function, as well as other things.  This particular steriod hormone can be converted into testosterone and estrogens and also might be able to control neuronal excitability and gene expression.

Or in other words, having an unusual level of this substance suggests that there is something going on that the body is trying to control.  Since most of the things on the list above are impacted in autism, might not this be something to focus on?

It is all well and good to have yet another study (34 and counting) that looks at what is basically idle speculation,  but wouldn't it be better to spend the research dollars investigating actual biological differences in people with autism and trying to find their source?


Bejerot S, Eriksson JM, Bonde S, Carlström K, Humble MB, Eriksson E. The extreme male brain revisited: gender coherence in adults with autism spectrum disorder. Br J Psychiatry. 2012 Apr 12. [Epub ahead of print]  PubMed PMID: 22500012 .  DOI: bjp.bp.111.097899
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